摘要
目的为了延缓混凝土初凝和终凝时间而不影响混凝土后期强度,对两种羟基羧酸盐类缓凝组分进行分析研究。方法分析两种缓凝组分在不同掺量下对普通硅酸盐水泥的凝结时间、扩展度、强度及水化热的影响规律,利用扫描电子显微镜观察水泥的微观结构特征。结果掺入缓凝组分后,水泥的凝结时间延长了,掺量为0.07%时物理性能最佳,此时初凝时间分别延长了299 min和218 min,扩展度分别延长了35 mm和30 mm,56 d抗折强度分别增加了12.22%和9.65%,56 d抗压强度分别增加了15.67%和11.39%;从微观结构的特征可以看出随缓凝组分掺量增加,水化速率减慢,各水化产物之间交叉连生,形成更为密实的网状结构,改善了水泥试样的后期强度。结论液体缓凝组分相较于固体缓凝组分能更好地起到缓凝作用,延缓了水泥水化反应及水化产物的生成时间,进而改善了生成物之间的搭接结构,提高了水泥后期强度。
In order to delay the initial and final setting time of concrete without affecting the later strength of concrete,two hydroxy carboxylate retarders with retarding components were analyzed and studied.The test was conducted to analyze the effects of two retarding components on the setting time,extension,strength and heat of hydration of ordinary silicate cement at different dosing levels,and the microstructural characteristics of the cement were observed by scanning electron microscopy.The setting time of the cement was prolonged after the incorporation of the retarding component,and the physical properties were best at the dosing of 0.07%,when the initial setting time was prolonged by 299 min and 218 min,the extension was prolonged by 35 mm and 30 mm,the flexural strength at 56 d was increased by 12.22%and 9.65%,and the compressive strength at 56 d was increased by 15.67%and 11.39%,respectively.As well as the phenomenon of electron microscopy,the slow setting component slowed down the hydration rate with the increase of admixture,and the hydration products were cross-linked with each other to form a more dense mesh structure,which improved the late strength of cement specimens.The liquid retarding component can play a better retarding role than the solid retarding component,which delays the hydration reaction of cement and the generation time of hydration products,thus improving the lap structure between the products and increasing the later strength of cement.
作者
丁向群
胡童童
李小慢
段锦涛
房延凤
DING Xiangqun;HU Tongtong;LI Xiaoman;DUAN Jintao;FANG Yanfeng(School of Materials Science and Engineering,Shenyang Jianzhu University,Shenyang,China,110168)
出处
《沈阳建筑大学学报（自然科学版）》
CAS
北大核心
2023年第4期716-722,共7页
Journal of Shenyang Jianzhu University：Natural Science
基金
国家自然科学基金项目(51808354)
辽宁省自然科学基金项目(20180550092)。
关键词
硅酸盐水泥
缓凝剂
凝结时间
水化热
抗压强度
抗折强度
portland cement
retarder
setting time
heat of hydration
compressive strength
flexural strength
